Ambulatory medical infusion pumps are a commercially successful and popular medical instrument. The pumps allow for the convenient continuous and calibrated delivery of a variety of medicines including but not limited to antibiotics, pain relieving drugs, and chemotherapy drugs.
The pumps have a fastener system that allows a cassette to be removably attached to the pump. A cassette has a soft pliable drug reservoir bag placed within a hard shell cassette made from a rigid plastic such as a poly-carbonate to protect the integrity of the bag. The reservoir bag has a first tube section positioned within the pump assembly on which the pumps presses against the cassette pump plate to draw or pump the medicine out of the bag.
The soft tube section is attached to microbore tubing that exits the pump assembly. The microbore tubing has a luer lock or similar connector attached to its distal end that allows connection to a intravenous infusion or subcutaneous delivery system. The microbore tubing resists any unintentional kinking or crimping thus assuring proper delivery of the drugs therethrough.
The pump plate of the cassette is permanently secured either by adhesive or sonic welding to the cassette shell to assure that the shell is not unintentionally removed from about the bag so that the bag does not become accidentally exposed and maintains its integrity against accidental puncture.
When the medicine infusion is terminated, the one cassette is easily removed. When the medicine needs to be changed, the one cassette is easily removed and another cassette with a second medicine is conveniently attached to the pump.
Because the reservoir bag has been in fluid contact with a patient, the used reservoir bag may contain bodily fluids that passed up though the tubing and into the bag. Thus, the reservoir bag is considered medical waste and must be disposed of accordingly. Many principalities now have laws that forbid medical waste from being placed in landfills. The preferred disposal method is by incineration. For proper incineration, the cassette with both the used reservoir bag and cassette shell need to be incinerated at relatively high temperatures compared to regular incineration temperatures of other waste products. The higher temperatures are needed for the proper decomposition of certain chemotherapy drugs and for certain rigid plastics such as poly-carbonate. The cassette shell is incinerated with the reservoir bag, even though the cassette shell can be easily re-sterilized and capable of storing another reservoir bag.
The pumps are used to deliver small amounts of drugs. A typical reservoir bag is capable of holding only one hundred milliliters (100 ml.). The pump thus can pump many cassettes each day as needed. The pump during its useful life can pump many thousands of cassettes over several years.
The increasing expense and difficulties of proper disposal of the cassette assembly necessitates that only the waste be disposed of and other parts be repaired and reused as possible. The reuse of the cassette shell can save much plastic and reduce the amount of unnecessary incineration and the unwanted particulates and gasses produced by incineration.